Peter Van der Beken - Fix for bug 740069 (Generate JS bindings in C++ with a python script for DOM objects on the main thread and in workers. Infrastructure and new bindings for XMLHttpRequest). Patch by bent/bz/bholley/jst/khuey/peterv, r=bent/bz/bholley/jlebar/khuey/peterv/sicking/smaug.